Rotation responsive disk activation and deactivation mechanisms

ABSTRACT

Embodiments of methods and systems for controlling access to information stored on memory or data storage devices are disclosed. In various embodiments, fluid-mediated modification of information or access to information is utilized. According to various embodiments, data storage devices designed for rotating access are described which include rotation-activated fluid control mechanisms.

CROSS-REFERENCE TO RELATED APPLICATIONS

“The present application is related to and claims the benefit of theearliest available effective filing date(s) from the following listedapplication(s) (the “Related Applications”) (e.g., claims earliestavailable priority dates for other than provisional patent applicationsor claims benefits under 35 USC § 119(e) for provisional patentapplications, for any and all parent, grandparent, great-grandparent,etc. applications of the Related Application(s)).

RELATED APPLICATIONS

For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation-in-part of U.S. patentapplication Ser. No. 11/124,924, entitled METHOD AND SYSTEM FOR FLUIDMEDIATED DISK ACTIVATION AND DEACTIVATION, naming Bran Ferren, EleanorV. Goodall, and Edward K. Y. Jung as inventors, filed 9 May 2005, whichis currently co-pending, or is an application of which a currentlyco-pending application is entitled to the benefit of the filing date.

For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation-in-part of U.S. patentapplication Ser. No. 11/124,923, entitled FLUID MEDIATED DISK ACTIVATIONAND DEACTIVATION MECHANISMS, naming Bran Ferren, Eleanor V. Goodall, andEdward K. Y. Jung as inventors, filed 9 May 2005, which is currentlyco-pending, or is an application of which a currently co-pendingapplication is entitled to the benefit of the filing date.

For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation-in-part of U.S. patentapplication Ser. No. 11/150,837, entitled METHOD AND SYSTEM FORROTATIONAL CONTROL OF DATA STORAGE DEVICES, naming Bran Ferren, EdwardK. Y. Jung, and Clarence T. Tegreene as inventors, filed 9 Jun. 2005,which is currently co-pending, or is an application of which a currentlyco-pending application is entitled to the benefit of the filing date.

For purposes of the USPTO extra-statutory requirements, the presentapplication constitutes a continuation-in-part of U.S. patentapplication Ser. No. 11/150,823, entitled ROTATION RESPONSIVE DISKACTIVATION AND DEACTIVATION MECHANISM, naming Bran Ferren, Edward K. Y.Jung, and Clarence T. Tegreene as inventors, filed 9 Jun. 2005, which iscurrently co-pending, or is an application of which a currentlyco-pending application is entitled to the benefit of the filing date.

The United States Patent Office (USPTO) has published a notice to theeffect that the USPTO's computer programs require that patent applicantsreference both a serial number and indicate whether an application is acontinuation or continuation-in-part. Stephen G. Kunin, Benefit ofPrior-Filed Application, USPTO Official Gazette Mar. 18, 2003, availableat http://www.uspto.gov/web/offices/com/sol/og/2003/week11/patbene.htm.The present applicant entity has provided above a specific reference tothe application(s) from which priority is being claimed as recited bystatute. Applicant entity understands that the statute is unambiguous inits specific reference language and does not require either a serialnumber or any characterization, such as “continuation” or“continuation-in-part,” for claiming priority to U.S. patentapplications. Notwithstanding the foregoing, applicant entityunderstands that the USPTO's computer programs have certain data entryrequirements, and hence applicant entity is designating the presentapplication as a continuation-in-part of its parent applications as setforth above, but expressly points out that such designations are not tobe construed in any way as any type of commentary and/or admission as towhether or not the present application contains any new matter inaddition to the matter of its parent application(s).

All subject matter of the Related Applications and of any and allparent, grandparent, great-grandparent, etc. applications of the RelatedApplications is incorporated herein by reference to the extent suchsubject matter is not inconsistent herewith.”

TECHNICAL FIELD

The present application relates, in general, to the control of access toinformation stored on memory or data storage devices. In particular, itrelates to control of access to information through modification of datastorage media.

BACKGROUND

Various methods have been used to control access to information storedon data storage devices such as CDs, DVDs, floppy disks, and so forth.Methods of controlling access to information are utilized for variousreasons including, for example, to limit unauthorized access tocopyrighted information. Such methods may involve requiring the use ofaccess codes provided, e.g., on data storage device packaging in orderto read information from a data storage device, or erasing data orpreventing reading of data from a data storage device following readingof the device.

SUMMARY

Embodiments of methods and systems for fluid mediated regulation ofaccess to information on data storage devices are disclosed. Features ofvarious embodiments will be apparent from the following detaileddescription and associated drawings.

BRIEF DESCRIPTION OF THE FIGURES

Features of the invention are set forth in the appended claims. Theexemplary embodiments may best be understood by making reference to thefollowing description taken in conjunction with the accompanyingdrawings. In the figures, like referenced numerals identify likeelements.

FIG. 1 illustrates a system including a disk drive;

FIG. 2 illustrates a computer system;

FIG. 3 illustrates parameters relating to rotation of a disk;

FIGS. 4A-4C illustrate angular velocity, its derivative, and its square,respectively;

FIG. 5 depicts a disk having a rotation activated fluid releasemechanism;

FIG. 6 depicts fluid release devices configured to release fluid inresponse to angular acceleration or deceleration;

FIGS. 7A and 7B depict a fluid release mechanism;

FIG. 8 illustrates a disk having machine readable data stored thereon;

FIG. 9 illustrates a disk having machine readable data stored thereon;

FIG. 10 illustrates a capillary valve mechanism;

FIG. 11 illustrates a further valve mechanism;

FIG. 12 illustrates a microvalve;

FIGS. 13A and 13B illustrate degradation of a portion of a data storagemedium produced by introduction of a fluid;

FIGS. 14A and 14B illustrate degradation of data produced byintroduction of a fluid;

FIGS. 15A and 15B depict blocking of reading of data by a fluid;

FIGS. 16A and 16B illustrate degradation of a portion of a data storagemedium produced by release of a fluid;

FIGS. 17A and 17B illustrate degradation of data produced by release ofa fluid;

FIGS. 18A and 18B illustrate optical interference with data readingproduced by release of a fluid;

FIGS. 19A and 19B depict degradation of a portion of a data storagemedium produced by a fluid acting in combination with an additionaldegradation inducing factor;

FIGS. 20A and 20B depict degradation of data produced by a fluid actingin combination with an additional degradation inducing factor;

FIGS. 21A and 21B depict a fluid blocking degradation of data by anadditional degradation inducing factor;

FIG. 22 depicts a disk having a rotation activated fluid releasemechanism;

FIGS. 23A-23C illustrate exemplary patterns of angular velocity, itsderivative, and its square, respectively;

FIGS. 24A-24C illustrate exemplary patterns of angular velocity, itsderivative, and its square, respectively;

FIG. 25 illustrates a data storage device having a plurality ofcentrifugally activated fluid release mechanisms;

FIGS. 26A and 26B depict an embodiment of a fluid switch;

FIGS. 27A and 27B depict another embodiment of a fluid switch;

FIGS. 28A and 28B illustrate blocking of reading of data by closing aswitch;

FIGS. 29A and 29B illustrate producing destruction of data by closing aswitch;

FIGS. 30A and 30B illustrate producing modification of data by closing aswitch;

FIG. 31 illustrates a data storage device with a fluid release mechanismactivatable over multiple uses;

FIGS. 32A and 32B depict a rotation activatable switch;

FIG. 33 illustrates different orientations of rotation activatableswitches;

FIG. 34 is a schematic diagram of a system including a data storagedevice;

FIG. 35 is a flow diagram of a method of activating a rotationactivatable control mechanism in association with reading data;

FIG. 36 is a flow diagram of a method of activating a rotationactivatable control mechanism in association with reading data;

FIG. 37 is a flow diagram of a method of activating a rotationactivatable control mechanism in association with reading data;

FIG. 38 is a flow diagram of a method of activating a rotationactivatable barrier in association with reading data;

FIG. 39 is a flow diagram of a method of controlling access to data on adisk;

FIG. 40 is a flow diagram of a method of controlling access to data on adisk;

FIG. 41 is a flow diagram of a method of manufacturing a data storagedevice;

FIG. 42 is a flow diagram of a method of operating a disk drive;

FIG. 43 is a flow diagram of a method of configuring a disk drive foruse with a rotation-sensitive disk;

FIG. 44 depicts a data storage device with a rotation activatable switchmechanism;

FIG. 45 depicts a data storage device including four rotationactivatable switch mechanisms;

FIGS. 46A and 46B illustrate a data storage device with arotation-responsive barrier portion;

FIGS. 47A and 47B illustrate a data storage device with arotation-responsive evaporating degradation barrier;

FIGS. 48A and 48B illustrate a data storage device with arotation-modifiable barrier portion; and

FIG. 49 is a flow diagram of a method of manufacturing a data storagedevice.

DETAILED DESCRIPTION

FIG. 1 illustrates a system 10, which may be a computer system or othersystem that includes a data storage device 24 configured for rotatingaccess. System 10 includes a processor 12, system memory 14, one or moreI/O devices 16, and disk drive 22, which is configured to receive a diskshaped data storage device 24. The system may also include a powersupply, not shown. Data, power and control signals may be transferredbetween system components via data bus 26. Processor 12 may be amicroprocessor. In this example, and in general, data storage device 24may be a CD, DVT, floppy disk, or any of various other data storagedevices configured for rotating access. Such data storage devices arefrequently disk shaped, but the invention is not limited to use withdisk shaped data storage devices.

As a specific example of the system depicted in FIG. 1, FIG. 2illustrates a computer system 28. Computer system 28 includes aprocessor 12, system memory 14, system bus 26, output device 32, whichin this example is a monitor, and input device 34, which in this exampleis a keyboard. System memory 14 includes read-only memory 36 andrandom-access memory 38. Device driver 40 is stored in random-accessmemory 38. Device driver 40 is used to control disc drive 30. Interface42 provides an interface between the computer system 28 and disk drive30. Control line 60 and data line 62 provide for the transfer of controland data signals between system 28 and disk drive 30.

Disk drive 30 includes receptacle 56, which is adapted to receive disk24. Disc 24 is rotated by motor 46. Positioner 48 adjusts the positionof the read head 50 with respect to disk 24.

FIG. 3 illustrates parameters associated with rotation of disk 24, whichmay be a disk shaped data storage device 24. Disk 24 may have a radiusr. If disk 24 is rotated with angular velocity ω, for example in acounterclockwise direction as depicted in FIG. 3, a particle at theperiphery of the disc will move with a tangential velocity V_(T). Thecentripetal acceleration a_(c) indicated by the grey arrow, will be ω²r.FIGS. 4A-4C depict the relationship between angular velocity, ω, anddω/dt and ω², which are proportional to angular acceleration, andcentripetal acceleration, respectively. Values of ω, dω/dt and ω²depicted in FIGS. 4A-4C are obtained when a disk that is initially atrest is rotated, increasing the rate of rotation over a first timeperiod 76 until a constant angular velocity is reached, then held at aconstant angular velocity for a second time period 78, and thengradually brought to rest again over a third time period 80. This isonly one example of many possible disk rotation patterns. In FIG. 4A,the angular velocity ω, represented by trace 70, is increased from zeroover first time period 76 of duration t₁ until a velocity ω₁ is reached,held constant at velocity ω₁ over second time period 78 having aduration t₂, and then decelerated back to zero angular velocity overthird time period 80, also of duration t₁. The corresponding angularacceleration, dω/dt, represented by trace 72 in FIG. 4B, has a value ofω₁/t₁ during first time period 76 and a value of −ω₁/t₁ during thirdtime period 80, and is otherwise zero. The centripetal accelerationexperienced by a particle at a given location on the disk will be equalto square of the angular velocity multiplied by the distance of thelocation from the center of rotation. Thus, for a particle at theperiphery (at a distance r from the center of rotation), the centripetalacceleration will be ω²r. Trace 74 in FIG. 4C represents ω², which isproportional to the centripetal acceleration. As can be seen in FIG. 4C,ω² increases non-linearly over first time period 76, is constant duringsecond time period 78, and decreases non-linearly over third time period80. As a disk rotates, a particle (which may be fluid or liquid) in oron the disk will experience an apparent “centrifugal force”,proportional to the centripetal acceleration and operating in theopposite direction, driving the particle toward the periphery of thedisk. During periods of angular acceleration and deceleration (e.g.,time periods 76 and 78 in FIGS. 4A-4C), a particle in or on the diskwill experience an angular force proportional to the angularacceleration dω/dt and of the same sign, with the direction of theangular force depending on whether the disk is accelerating ordecelerating.

FIG. 5 depicts an embodiment of a disk 100 having a rotation activatedfluid release mechanism 101. Fluid release mechanism 101 may includefluid chamber 102. Fluid chamber 102 may contain a degradation inducingfluid 104, which is retained in chamber 102 by pressure sensitive fluidbarrier 106. A degradation sensitive region 110 located within a chamber108 may be located radially outward of fluid chamber 102. When disk 100is rotated, centrifugal force F_(C), indicated by a black arrow, movesfluid 104 toward fluid barrier 106. The fluid release mechanism in FIG.5 is sensitive to centripetal acceleration (‘centrifugal force’).

Changing the orientation of the fluid release mechanism can make themechanism sensitive to forces associated with angular acceleration, ordeceleration. Such a device may be obtained, for example, by orientingfluid release mechanisms 122 and 124 on disk 120 as depicted in FIG. 6.A positive angular velocity ω is obtained when the direction of rotationof disk 120 is as indicated by the gray arrow. Angular acceleration willproduce inertial force F_(A) in fluid release mechanism 122, in thedirection indicated by the black arrow. Angular deceleration willproduce inertial force F_(D) in fluid release mechanism 122, in thedirection indicated by the black arrow. Thus, fluid will be releasedfrom fluid release mechanism 122 during angular acceleration ofsufficient magnitude, and fluid will be released from fluid releasemechanism 124 during angular deceleration of sufficient magnitude.

As depicted in FIG. 7A, F_(C), drives fluid 104 against fluid barrier106 to produce a pressure differential across fluid barrier 106, suchthat the pressure P₁ on the radially inward side of fluid barrier 106(i.e., the side toward fluid chamber 102) is higher than the pressure P₀on the radially outward side of fluid barrier 106 (i.e., the side towarddegradation sensitive region 110). Air vents 112 and 114 may be includedto permit the movement of fluid within chamber 102 and 108. When thepressure differential becomes large enough, fluid barrier 106 mayrupture, break down, or otherwise release fluid 104 so that it movesinto chamber 108, where it may cause degradation of degradationsensitive region 110. FIG. 7B depicts the fluid barrier in ruptured form106′. In this example, fluid barrier 106 is a frangible fluid barrier.Pressure sufficient to permit movement of fluid from the reservoir maybe obtained by spinning the substrate. If an optical disk is used, insome embodiments pressure sufficient to permit movement of fluid may beobtained by spinning the substrate in an optical disk drive at normalread speeds, while in other embodiments, pressure across the pressuresensitive barrier sufficient to permit movement of fluid from thereservoir may be obtainable by spinning the substrate in an optical diskdrive at speeds above normal read speeds. Similarly, if the data storagedevice is a magnetically readable disk, pressure across the pressuresensitive barrier sufficient to permit movement of fluid from thereservoir is obtainable by spinning the substrate in a magnetic diskdrive at normal read speeds in some embodiments, while in otherembodiments pressure across the pressure sensitive barrier sufficient topermit movement of fluid from the reservoir is obtainable by spinningthe substrate in a magnetic disk drive at speeds above normal readspeeds.

Machine readable data is commonly stored in a binary code, which may bestored in various materials that can exist in two different states. Forexample, data may be stored in a pattern of electrical potentials,magnetized regions, optically transmissive regions, or opticallyreflective regions, among others, as known or as may be devised by thoseof skill in the relevant arts. A degradation sensitive region of a datastorage device may include any portion of the data storage device thatmay be modified in some way to render information stored in the regioninaccessible or unusable in some way. ‘Degradation’ may includemodification of data stored in a data storage medium. A first state inthe data storage medium may represent a ‘1’, while a second state mayrepresent a ‘0’. Various other coding schemes may be used, which mayinclude more than two different states. Modification of data values mayinclude setting all data values to a ‘1’, setting all data values to a‘0’, resetting data values to a random value or to some pattern (e.g.,alternating ‘1’s and ‘0’s), or reducing the signal-to-noise ratio of thestored data. Degradation may include destruction of the data storagemedium so that no data may be stored therein. Degradation of adegradation sensitive region may include destruction or modification ofa substrate or coating located adjacent or near a data storage medium.If data is read optically, with the use of light transmitted through atransparent substrate, reading of data may be blocked, for example, bymodifying or degrading the substrate to block or hinder transmission oflight through the substrate.

In some embodiments, degradation may affect all or most of the datastored on a disk, with degradation considered to include destruction ormodification of data, destruction or modification of a data storagemedium, or destruction or modification of a substrate or coating layeradjacent or near a data storage medium. In other embodiments, all orportions of data on a data storage device may be rendered inaccessibleby degrading a subset of data on the data storage device that containsinformation necessary for reading data stored on other parts of the datastorage device. For example, as depicted in FIG. 8, data of interest(which might be, for example, a computer program or an audio or videodigital recording) may be distributed to multiple locations on datastorage device 150. In order to retrieve the data of interest in usableform, it may be read from the appropriate location in the appropriateorder, as specified by index information stored in disk region 152. Inthe present exemplary embodiment, disk region 152 may specify that datamay be read from first data region 154, second data region 156, thirddata region 158, fourth data region 160, fifth data region 162 and sixthdata region 164, in that sequence. Thus, in order to render the datastored in first through sixth data regions 154 through 164 unusable, itmay be sufficient to render data stored in disk region 152 inaccessible,for example by degradation of data, data storage medium, and/orsubstrate, as described above.

Various other methods of controlling access to data on a disk by causingdegradation of a limited portion of the disk may also be used. Anotherexample is depicted in FIG. 9. In FIG. 9, disk 170 includes data region172 containing data of interest in encrypted form. Key region 174contains a decryption key that may be used to decrypt data stored indata region 172. Degradation of key region 174 may thus be sufficient toblock access to data stored in data region 172.

In some embodiments, an index or key portion of data may containinformation necessary for reading data from other regions of the datastorage device. Degradation of index or key data thus causes“deactivation” of the data storage device. In other embodiments, anindex or key region may contain a code that blocks reading of data fromthe disk, e.g., because after the information has been read from thedisk, reading is discontinued by the disk drive or program controllingreading of data from the disk. Degradation of such key or indexinformation then “activates” or enables reading of data from the datastorage device. As a further alternative, the key or index informationmay activate or deactivate selected portions of the data storage device,so that (for example) different data may be read from the data storagedevice on the first reading than on the subsequent readings.

FIGS. 5, 7A and 7B depict exemplary embodiments in which a pressuresensitive fluid barrier 106 is a frangible barrier. Various otherbarrier or valve structures that open in response to fluid pressure,including but not limited to capillary breaks, hydrophobic breaks, orhydrophobic valves, may also be used. FIGS. 10 and 11 depict additionalexemplary fluid barriers. In FIG. 10, a first chamber 200 and secondchamber 202 are separated by a restricted diameter valve region 204.Valve region 204 may be any of various types of passive or capillaryvalves, for example, as described in “Design and Fabrication of PolymerMicrofluidic Platforms for Biomedical Applications,” Madou et al., ANTEC2001, pp. 2534-2538; “Design Analysis of Capillary Burst Valves inCentrifugal Microfluidics,” Zeng et al., Tech. Proc. of μTAS, May 2000,Enschede, The Netherlands, pp. 493-496; U.S. Pat. No. 6,591,852 and U.S.Pat. No. 6,296,020, all of which are incorporated herein by reference intheir entirety. Such valves may block the movement of fluid unless asufficiently high pressure differential is applied across therestriction. In some embodiments, if an aqueous fluid is used, andchambers 200 and 202 and valve regions 204 may be formed in ahydrophobic material, an abrupt reduction in channel diameter, as occursat entrance 206 of valve region 204, may obstruct the flow of fluid.Alternatively, a capillary break, or channel widening, as at exit 208 ofvalve region 204 may function as a passive or capillary valve. Asdepicted in FIG. 11, a valve region 224 between chambers 220 and 222 mayalso be formed by the application of a surface treatment 226 to theinterior of valve region 224. For example, a hydrophobic surfacetreatment 226 may be used to obstruct the flow of an aqueous fluidthrough valve region 224, while a hydrophilic surface treatment mayobstruct the flow of a non-polar fluid through valve region 224.Alternatively, surface treatment 226 may include a dried material that,when dissolved in the fluid, modifies the surface tension of the fluid.

Different types of microvalves may be used in various embodiments. Insome embodiments, micromechanical valves may include elements thatphysically block a fluid channel, and are controllable by various means.Such micromechanical valves may include, for example colloidal orpolymeric valve elements that can be moved or changed in size orconfiguration to open the valve. A few examples are described, forexample in U.S. Pat. Nos. 6,837,476, 6,802,489, and 6,793,753, all ofwhich are incorporated herein by reference in their entirety FIG. 12depicts in schematic form a fluid chamber 240 separated from adegradation sensitive region 242 by a microvalve 244.

Degradation of data may take place by various mechanisms, and mayinclude degradation or modification of data, data storage medium, and/orsubstrate. Degradation of the data storage medium may include one ormore of destruction of the data storage medium, modification of the datastorage medium, modification of data stored in the data storage medium,and modification of signal-to-noise ratio of data stored in the datastorage medium. Degradation may take place directly in response to adegradation inducing influence, or it may be initiated by a degradationinducing influence but continue to completion after removal of thedegradation inducing influence. This may be the case, for example, ifthe degradation inducing influence provides input of an activationenergy sufficient to overcome an energetic barrier and set off achemical process that proceeds without further input of energy onceinitiated. A degradation inducing influence may produce degradationdirectly, or may function as an intermediary to enable or initiateaction by a direct degradation inducing influence. Degradation mayinclude various combinations of two or more degradation mechanisms, andin some embodiments may be produced by synergistic or cooperativeeffects of two or more degradation inducing or producing factors orinfluences. In general, release of fluid may produce (directly orindirectly) a modification of a modifiable feature on a data storagedevice. Examples of modifiable features include, but are not limited to,mechanical properties, optical properties, electrical properties,magnetic properties, or chemical properties. FIGS. 12-20 provideexamples of a number of fluid-induced degradation mechanisms, caused byintroduction of fluid into a region of a data storage device or removalof fluid from a region of a data storage device. In some embodiments,degradation may occur substantially simultaneously with introduction offluid, e.g., substantially instant destruction of data may be obtained.

In FIG. 13A, a portion of a data storage device 250 is depicted. Datastorage device 250 includes a substrate 252 and a data storage medium254 storing binary data 256, represented by a pattern of black blocksrepresenting one of two states of data storage medium 254. A channel 258runs through substrate 252. Channel 258 is empty in FIG. 13A. In FIG.13B, fluid 259 has filled channel 258. The presence of fluid 259 causesdegradation substrate 252 to form degraded substrate 252′, through whichdata 256 cannot be read. Degradation of substrate 252 may include achange in a material property of the substrate or a change in shape orconformation of the substrate material, such as thickness or surfacetexture. Material properties may include optical properties such asreflectivity, index of refraction, transmissivity, light scattering,electrical properties, magnetic properties, and so forth. Modificationsto material properties, shape, or conformation may be caused by a phasechange, chemical reaction, melting, etching, corrosion, etc. of thesubstrate material due to exposure to fluid. Many specific combinationsof substrate material and degradation inducing fluid may be used;examples include the combination of water (or other aqueous fluids) withwater-absorbing polymers that expand upon exposure to water; thecombination of an oxidation-inducing fluid in combination with asubstrate containing colorless compounds that may be oxidized to formcolored compounds, such as indigo carmine, methylene blue, thionin,gallocyanine, among others, as discussed in U.S. Pat. No. 6,011,772,which is incorporated herein by reference.

FIGS. 14A and 14B illustrate a portion of a data storage device 260.Data storage device 260 includes a substrate 262 and a data storagemedium 264 storing binary data 266, again represented by a pattern ofblack blocks representing one of two states of data storage medium 264.A channel 268 runs between substrate 262 and data storage medium 264.Channel 268 is empty in FIG. 14A. In FIG. 14B, fluid 269 has filledchannel 268. The presence of fluid 269 causes degradation of data 266stored in data storage medium 264. Degraded data 266′ is readable butdoes not contain the correct information. Modification or destruction ofdata may be caused by a phase change or chemical produced in the datastorage medium due to exposure to the degradation inducing fluid. Forexample, in optical disks, a reflective layer of metallic aluminum maybe used as a data storage medium. Exposure of metallic aluminum to anaqueous salt solution, for example, may result in oxidation of thealuminum to form non-reflective hydroxy salts.

FIGS. 15A and 15B illustrate a portion of a data storage device 270,which includes a substrate 272, data storage medium 274 containing data276, and fluid channel 278. Data is read through substrate 272 andchannel 278 when channel 278 is empty. Reading could be by variousmeans, for example, optically, magnetically, electrically, and so forth.As shown in FIG. 15B, when fluid 279, which is opaque ornon-transmissive to the read signal, fills channel 278, reading of datathrough substrate 272 is blocked. Fluid 279 may absorb, reflect,scatter, or otherwise interfere with a signal used to read data 276.Fluids may absorb, reflect, scatter, or otherwise be non-transmissive toelectrical signals, optical signals, magnetic signals, or various othersignals used to read data 176 from data storage medium 274. Fluids thatmay be used to block optical reading of data include various dyesolutions. Fluids containing ferric and/or ferrous materials may be usedto block magnetic reading of data include.

FIGS. 16A and 16B illustrate degradation of a region of a data storagedevice 280 produced by release of a fluid from the region. Data storagedevice 280 includes substrate 282, data storage medium 284 containingdata 286, and channel 288 containing fluid 289. Data 286 may be readthrough substrate 282 and fluid 289. In FIG. 16B, fluid 289 has beenrelease from channel 288 so that it is empty (i.e., it fills with airthat enters via an air channel when fluid 289 is released). In theabsence of fluid 289, the substrate degrades to degraded substrate 282′,which is non-transmissive to the read signal and thus prevents readingof data 286. Substrate 282 may degrade when exposed to one or morecomponents of air, or it may be an unstable material that is preservedby the presence of the fluid but degrades with the release of fluid fromchannel 288. Possible combinations of substrate and fluid that exhibitthese properties include substrates that include a colorless compoundthat is oxidized upon exposure to air to form a colored compound (e.g.methylene blue, thionin, indigo carmine, or gallocyanine) used incombination with an oxidation-protective fluid such as a buffer.

Similarly, FIGS. 17A and 17B illustrate degradation of data produced byrelease of a fluid from a region 290 of a data storage device. Fluidchannel 298 is formed between substrate 292 and data storage medium 294,which contains data 296. Fluid 299 is contained in fluid channel 298. InFIG. 17B, fluid 299 has been released, leaving channel 298 empty. In theabsence of fluid 299, data 296 stored in data storage medium 294 ismodified or degraded to degraded data 296′, which may be readable butdoes not contain usable information. Possible combinations of datastorage medium and fluid that result in such a degradation patterninclude metallic data storage media used in combination with anoxidation-protective fluid.

FIGS. 18A and 18B illustrate optical interference with data readingproduced by release of a fluid. In FIG. 18A, portion 300 of a datastorage device includes a substrate 302, data storage medium 304containing data 306, and channel 308 containing fluid 309. Fluid 309 mayhave an index of refraction that matches that of substrate 302, topermit optical reading of data 306. When fluid 309 is released fromchannel 308, as depicted in FIG. 18B, a mismatch between the index ofrefraction of substrate 302 and air contained in channel 308 may hinderreading of data 306.

In FIGS. 19A and 19B, a portion of data storage device 320 is depictedwhich includes substrate 322, data storage medium 324, and channel 328between substrate 322 and data storage medium 324. Data storage medium324 contains data 326. Data storage device 320 is exposed to anadditional degradation inducing factor or influence 330, which may be,for example, heat, light, other forms of electromagnetic radiation,pressure, a magnetic field, or an electrical field. Additionaldegradation inducing factor 330 has no effect by itself, but, asdepicted in FIG. 19B, when fluid 329 is introduced into channel 328,fluid 329 and additional degradation inducing factor 330 actsynergistically or in cooperation to produce degradation of substrate322 to degraded form 322′, to block reading of data 326. Additionaldegradation inducing factor 330 may function to provide activationenergy for a reaction involving fluid 329 and substrate 322. Forexample, fluid 329 may contain a reactant that will participate in areaction (e.g., a reduction or oxidation reaction) upon exposure to anadditional degradation inducing factor as listed above to produce achange in color or dimension of substrate 322.

FIGS. 20A and 20B depict a portion of data storage device 340, whichincludes substrate 342 and data storage medium 344, which containsstored data 346 and has a channel 348 running through it. Data storagemedium 344 is exposed to additional degradation inducing factor 350.Additional degradation inducing factor 350 has no effect until, as inFIG. 20B, fluid 352 is introduced into channel 348. Additionaldegradation inducing factor 350 may be, for example, heat, light, otherforms of electromagnetic radiation, pressure, a magnetic field, or anelectrical field. Fluid 352 and additional degradation inducing factor350 act in combination to produce degradation of data 346 to degradedform 346′. As discussed above, additional degradation inducing factormay provide activation energy to a chemical reaction between fluid 352and data 346 stored in data storage medium 344.

In another embodiment, a fluid may be released from a region of a datastorage device to permit exposure of a degradation sensitive region todegradation by an additional degradation inducing factor. In FIG. 21A, aportion of data storage device 360 includes substrate 362 and datastorage medium 264 containing data 366. Fluid 370 contained withinchannel 368 may block exposure of data storage medium 364 to degradationinducing factor 372. As shown in FIG. 21B, when fluid is released fromchannel 368, data storage medium 364 is exposed to degradation inducingfactor 372, which converts data stored therein to a degraded form 366′.For example, degradation inducing factor 372 may be light, and fluid 370may be a fluid that blocks transmission of light, examples of which areprovided above. As an alternative, degradation inducing factor 372 maybe a magnetic field, and fluid 370 may be a fluid that blocks orotherwise modifies transmission of the magnetic field, for example, afluid containing ferrous and/or ferric materials. Various combinationsof degradation inducing factors and blocking fluids may be designed foruse in various embodiments, by a practitioner of skill in the relevantarts.

The specific type of fluid that may produce degradation of substrate,data storage medium, or data, as illustrated in the forgoing examples,will depend upon the materials used as substrate and data storagemedium, and the method by which data is read. Fluids may have variouschemical, optical, electrical, physical, thermal, and/or otherproperties selected to work in combination with data storage devicematerials, and, in some embodiments, with additional degradationinducing influences, to produce a desired effect. Similarly, theadditional degradation inducing influence may be selected based uponchoice of substrate, data storage medium, and fluid type. Exemplarycombinations have been presented. Additional combinations will beapparent to the practitioner of skill in the art, and the foregoingexamples are not intended to be limiting. As used herein, the term‘fluid’ may include a variety of materials having fluid-like properties,including but not limited to liquids, gases, powders, and variouscombinations thereof. The term fluid encompasses both homogeneous andinhomogeneous materials or mixtures. Combinations may include emulsions,suspensions, and slurries. In some cases, the fluid may be a combinationmade up of a fluid or fluid-like carrier material and an activecomponent carried in the carrier material. The carrier material mayconfer upon the mixture its fluid properties, while the active componentmay confer up on the fluid its degradation-inducing ordegradation-preventing properties.

As noted previously, release of fluid may cause degradation or othermodification of a disk immediately upon its release, or it may initiatea process which may take place over some period of time followinginitiation (by selecting the process appropriately, the process may takeplace over seconds, minutes, hours, days or weeks, depending upon theparticular chemical processes involved). If degradation is notimmediate, it may be satisfactory to initiate the degradation processbefore any data has been read from the disk, and any fluid releasemechanism that is activated at some point during a read of data from thedata storage medium may be sufficient. If, however, fluid releaseproduces immediate data degradation when it enters the fluid sensitiveor fluid responsive region of the data storage medium, then fluidrelease must be controlled in such a manner that it occurs only afterdata has been read from the data storage device. If the fluid causesdegradation of only key or index data, then it may be acceptable ordesirable to release fluid after key or index data has been read fromthe disk, but possibly prior to reading of data from other areas of thedisk. In various embodiments, it may be desirable to control the timingof the release of fluid.

FIG. 22 is an exemplary embodiment of a data storage device configuredsuch that fluid released in such a way that it enters a fluid responsiveregion following a single read of data from the device. FIG. 22 depictsa data storage device 400 that includes a disk-shaped substrateconfigured for rotating access. Machine-readable data may be stored in adata storage medium carried by the substrate. The data storage devicealso includes a fluid release device and associated fluid circuitconfigured to deliver fluid to a portion of the data stored on the datastorage device following a single use of the device. Data storage device400 includes reservoir 404, which is adapted to contain fluid 406. Datastorage device 400 also includes fluid responsive or fluid sensitiveregion 402, which is configured to receive fluid from reservoir 404 andupon receipt of fluid to undergo a change, which may include any ofvarious types of changes or modifications as depicted in the previousexamples. A pressure sensitive barrier 408 between reservoir 404 andfluid responsive region 402 is adapted to prevent flow of fluid fromreservoir 404 to fluid responsive regions 402 if the pressure dropacross pressure sensitive barrier 408 is below a first pressuredifference, and to permit flow of fluid from reservoir 404 to fluidresponsive region 402 if the pressure drop exceeds the first pressuredifference. First radial channel segment 410 extends radially outwardfrom pressure sensitive barrier 408 and is adapted to receive fluid fromreservoir 404. Connecting channel segment 412 is adapted to receivefluid from first radial channel segment 410. Second radial channelsegment 414 extends radially inward from connecting channel segment 412to fluid responsive region 402, and is adapted to deliver fluid fromconnecting channel segment 412 to fluid responsive region 402.

In use, fluid 406 moves from reservoir 404 when the centrifugal force issufficient to cause barrier 408 to fail, and moves down first radialchannel segment 410 to connecting channel segment 412, driven bycentrifugal forces. Fluid 406 may move into connecting channel segment412 driven by angular acceleration forces, or may be drawn in bycapillary forces. Fluid may move through second radial channel segment414 to fluid responsive region 402 when centrifugal forces decrease to alevel where they are surpassed by capillary forces in second radialchannel segment 414 and fluid responsive region 402. Centrifugal forceswill initially reach the level needed to cause fluid to flow throughpressure sensitive barrier 408 when the disk rotates as reading of thedisk is initiated, and centrifugal forces may decrease sufficiently toallow fluid to flow into second radial channel segment 414 and to fluidresponsive region 402 when the disk decelerates at the end of reading.

In some embodiments, the pattern of disk rotation that occurs during asingle use or reading of a disk may not match the simple accelerationpattern depicted in FIGS. 4A-4C, in which acceleration to a constantvelocity is eventually followed by deceleration back to rest. If thedisk is read in sequence, in some cases the angular velocity may bevaried as a function of distance of the read head from the center of thedisk, in order to provide a constant linear velocity at the position ofthe read head. Moreover, depending on how the data is distributed on thedisk, reading may involve multiple accelerations and decelerations. Forexample, the angular velocity, ω, and corresponding dω/dt and ω², may beas depicted in FIGS. 23A-23C. In order to control the timing of fluidrelease with respect to reading of some or all of the data from thedisk, the expected pattern of disk rotation during reading of the diskmay be taken into account, the inertial forces due to angular andcentripetal acceleration determined, and pressure sensitive barrier andfluid channels on the disk must be configured appropriately. Theorientation and break pressure of each pressure sensitive barrier may beselected according to the anticipated rotation pattern, and capillaryforces produced by fluid channels such as second radial channel segment414 in FIG. 22, which may depend upon channel dimensions and combinationof channel material and fluid properties, may be selected to operate incooperation with inertial forces.

FIGS. 23A-23C illustrate A, and corresponding dω/dt and ω², in a casewhere the data storage medium is driven by a motor that produces aconstant torque, and hence constant acceleration or deceleration. Asshown in FIG. 23A, angular velocity ω, represented by trace 419,increases linearly over time interval 422 to a first constant velocityat peak 424. ω decreases linearly over time interval 426 to a secondconstant velocity 428, increases again over time interval 430 to a thirdconstant velocity, 432, decreases over time interval 434 to fourthconstant velocity 436, and increases again over time interval 438 toreach fifth constant velocity 440, which is the same as third constantvelocity 432. Finally, ω decreases over time interval 442 until thesubstrate is at rest.

Corresponding values of dω/dt and ω² are indicated by traces 420 and 421in FIGS. 23B and 23C, respectively. It can be seen from FIG. 23B thatover time intervals 422, 430, and 438, the angular acceleration dω/dt isof constant amplitude, but the duration of the acceleration pulsesvaries depending on the corresponding change in angular velocity.

Similarly, over time intervals 426, 434, and 442, dω/dt is of constantnegative amplitude, but the duration of the deceleration pulses variesdepending on the corresponding change in angular velocity. The start ofdisk use could be detected, for example, by providing a fluid releasemechanism that was sensitive to long-duration angular acceleration pulse444. Similarly, the end of disk use could be detected by providing amechanism sensitive to long-duration angular deceleration pulse 446.Centrifugal forces, proportional to ω², may show peaks, e.g., 446, 450,and 458 as depicted in FIG. 23C, that may be differentiated byduration-sensitive mechanisms, offering further possibility forcontrolling the timing of disk activation or deactivation.

FIGS. 24A-24C depict a further pattern of angular velocity ω, indicatedby trace 530 in FIG. 24A. The corresponding pattern of angularacceleration dω/dt is indicated by trace 532 in FIG. 24B, and thecorresponding value of ω², proportional to the associated “centrifugalforce” is represented by trace 534 in FIG. 24C. In the example of FIGS.24A-24C, the magnitude of angular acceleration dω/dt (and the associatedinertial forces) is variable, so different segments of disk use may becharacterized by differences in amplitude as well of duration in angularacceleration forces. Note that angular acceleration peaks 536 and 540differ in both amplitude and duration; similarly, angular decelerationpeaks 538 and 544 differ in amplitude and duration. Centrifugal forces,proportional to ω², as indicated by trace 534 in FIG. 24C, similarlyshow differences in amplitude and duration (e.g., peaks 546 and 548)that may be detected by appropriately configured fluid release devices.

In some embodiments, it may be desirable to produce activation of afluid release mechanism at a particular time during a use of a datastorage device. This can be accomplished easily in the case that angularacceleration only occurs at the beginning of each use, and angulardeceleration occurs only at the end of each use (as depicted in FIGS.4A-4C) by orienting fluid release devices so that they are sensitive toangular acceleration or deceleration, as desired. If multiple angularaccelerations and decelerations occur during a single use, as depictedin FIGS. 23A-23C and 24A-24C, then it may be possible to set a thresholdvalue for response of a fluid release device to angular acceleration, sothat fluid may be released during the highest acceleration conditionthat occurs during use of the data storage device. Similarly, athreshold value may be set for angular deceleration, so that fluid maybe released during the highest deceleration condition that occurs duringuse of the data storage device. In some embodiments, amplitude of diskacceleration may not provide a sufficient basis for controlling timingof fluid release during use of the disk, but duration of accelerationmay be used for identifying a time when fluid should be released. Forexample, if a constant torque motor is used, a long acceleration periodwill be necessary to bring the disk up to speed initially, and a longdeceleration period will be necessary to bring the disk back to rest atthe end of a use, but changes in speed during a single use may involveshorter periods of acceleration or deceleration. Therefore, thebeginning and end of a single use may be identified through the use of amechanism that is responsive to acceleration or deceleration,respectively, of a specified duration. Fluid valves that are sensitiveto the duration of exposure to rotational forces may be used.

Another method for controlling timing of fluid release during use of adata storage device is to combine fluid release with exposure of afluid-sensitive portion of the data storage device to an additionaldegradation inducing influence. Degradation inducing influence mayinclude heat, light, other forms of electromagnetic radiation, pressure,a magnetic field, or an electrical field. The use of fluid release incombination with an additional degradation inducing factor is shown inFIGS. 20A and 20B or FIGS. 21A and 21B. In these examples, degradationis produced by combining release of a fluid, which may occur at somepoint during a use of a device, with an additional factor. For example,if the additional factor is a beam of light from a read head, the diskmay be configured so that the degradation sensitive region is located ona portion of the disk that is exposed to light from the read head onlyonce during use of the device, e.g. at the end of use when the read headpasses over the edge of the disk as it returns to its ‘parked’ position.Providing fluid is release at some time during use of the device, thedegradation sensitive portion of the disk will respond when it isexposed to light, which occurs at a well-defined time during use of thedisk. Accordingly, the degradation is produced or initiated at awell-defined time even if the timing of fluid release is not preciselycontrolled, but is known to happen at some point during use of the disk.

The previous exemplary embodiments are suitable for producing orinitiating disk activation or deactivation by modifying a feature of adata storage device at some point during a single use of the device.However, in many cases it may be desirable to produce disk deactivation(or modify the availability of certain data on the disk) after multipleuses of the data storage device. For example, a demo disk may be useablefor a fixed number of uses before it becomes unusable, or a rental DVDcontaining a movie may be usable for a limited number of viewings.

FIG. 25 depicts an exemplary data storage device that is configured forproducing disk deactivation after a selected number of uses of the disk.One approach for detecting multiple uses of a data storage device (e.g.,for the purpose of limiting access to the data storage device after acertain number of uses) is to provide methods for modifying the diskduring normal use in such a way that structures on the disk that aremodified by use are modified in sequence over multiple uses, rather thanall being modified by a single use. This may be accomplished by settingdifferent thresholds for the different structures, and driving the diskdifferently (e.g. at a higher speed) on each subsequent use. FIG. 25illustrates a data storage device 750 with a plurality of centrifugallyactivated fluid release devices 752, 754, 756, and 758, of the typedepicted in FIGS. 5, 6A and 6B. Fluid release device 752 includes fluidchamber 758 containing fluid 760, fluid barrier 762, and degradationsensitive region 764. Similarly, fluid release device 754 includes fluidchamber 766 containing fluid 768, fluid barrier 770, and degradationsensitive region 772, fluid release device 756 includes fluid chamber774 containing fluid 776, fluid barrier 778, and degradation sensitiveregion 780, and fluid release device 758 includes fluid chamber 782containing fluid 784, fluid barrier 786, and degradation sensitiveregion 788. Fluid release devices 752, 754, 756, and 758 may beconfigured to be activated in sequence over a number of uses of datastorage device 750. This may be accomplished by various methods. In oneembodiment, fluid barriers 762, 770, 778, and 786 may be configured tobreak at different pressures. For example, the first fluid barrier maybreak at a rotation speed obtained during normal use of the device. On asubsequent use of the device, activation of the first fluid releasedevice may be detected, and the drive may produce rotation a firstabove-normal speed of rotation for a period sufficient to activate asecond fluid release device. Similarly, on each subsequent use of thedevice, activation of at least the most recently activated fluid releasedevice may be detected, and following detection, the disk may be rotatedat a speed of rotation sufficient to activate the next fluid releasedevice. Thus, a selected number of uses of the device may be detected,until the maximum allowable number of uses has been reached, and thedisk is deactivated. The device and methodology associated with FIG. 25may be carried out with the use of a modified disk drive or drivecontroller, in order to obtain higher rotations with each used of thedisk. However, by appropriately configuring the rotation sensitivestructures on the disk, the sensitivity of each structure to rotationmay be modified by release of fluid by the preceding fluid releasemechanism. Accordingly, modification of each structure other than thefirst is dependent upon prior modification of at least one otherstructure. Modification of a first structure may modify the sensitivityof another structure by various methods, for example, by releasing afluid that dissolves a barrier to air or fluid movement, by opening orclosing an electrical circuit to produce modification of an electricallysensitive fluid barrier (e.g., formed by an electroactive polymer,piezoelectric material, or MEMS structure).

A rotation activated fluid switch capable of opening or closing anelectrical circuit can be constructed as depicted in FIGS. 26A and 26Band 27A and 27B. The fluid switch of FIGS. 26A and 26B is closed byrelease of fluid from a fluid chamber. FIG. 26A shows first chamber 500containing an electrically conductive fluid 502, which is retained inchamber 500 by barrier 504. Also shown is second chamber 506, whichincludes electrical contact 508 connected to lead 510, and electricalcontact 512 is connected to lead 514. Second chamber 506 may initiallybe filled with air or with a non-conductive fluid. When fluid 502 issubjected to a force (e.g., a centrifugal force), it may break throughbarrier 504 (to form ruptured barrier 504′) and enter second chamber506. Air vents 520 and 522 may be required to permit fluid 502 to movefrom first chamber 500 to second chamber 506. When fluid 502 fillssecond chamber 506, fluid 502 forms an electrical connection betweencontact 508 and 512, thus permitting the structure of FIGS. 26A and 26Bto function as a switch. Leads 510 and 514 may be connected to varioustypes of electronic circuitry.

FIGS. 27A and 27B depict another embodiment of a fluid activated switch,similar to that depicted in FIGS. 26A and 26B except that release offluid from the first chamber causes the switch to open rather than toclose. In FIG. 27A, a structure is provided which includes a firstchamber 600 filled with conductive fluid 602, and a barrier 604 thatprevents the flow of fluid 602 into second chamber 614. In thisembodiment, electrical contact 606, connected to lead 608, andelectrical contact 610, connected to lead 612, are located in firstchamber 600. Again, air channels 620 and 622 are provided to permit theflow of fluid from first chamber 602 to second chamber 614 when barrier604′ is broken or ruptured, as depicted in FIG. 26B. If fluid 602 is aconductive fluid, the electrical circuit (switch) between leads 608 and612 is closed when fluid 602 is contained in first chamber 600, and isopened when fluid 602 breaks through barrier 604 and moves into secondchamber 614.

Opening or closing of a switch (which may be a fluid switch or othertype of switch) may be utilized in various ways to produce modificationor degradation of data, or render data unreadable or otherwiseinaccessible. Several methods are illustrated in FIGS. 28A-28B, whichare exemplary of a larger number of methods that may be used.

FIGS. 28A and 28B illustrate blocking of reading of data by closing aswitch. A system 650, which is a portion of a data storage device suchas an optically readable disk, is shown. The data storage deviceincludes substrate layer 562 and data storage medium 654, in which isstored binary data 656. Data 656 may be read through substrate layer652, e.g., via light delivered and sensed by an optical read head.Region 658 of substrate layer 652 includes a voltage sensitive material.Lead 664 and lead 666 are connected to opposite sides regions of voltagesensitive region 658. Voltage source 660 and switch 662 are connected inseries between leads 664 and 666. When switch 662 is open, region 658 ofsubstrate 652 is in a state that permits optical reading of data 656.When switch 662 is closed (with closed configuration indicated by 662′),however, as depicted in FIG. 28B, voltage sensitive region 658transforms to a different state, indicated by reference number 658′,through which data 656 cannot be read. Voltage sensitive region 658 maybe formed, for example, from a liquid crystal or various other materialsthat are responsive to an applied voltage. Voltage source 660 mayinclude any of a number of devices or structures that are capable ofstoring or generating electrical potentials. For example, piezoelectricstructures on the disk may convert vibration or other motion in the diskto voltages. Alternatively, electrostatic charges may be accumulated onthe rotating disk. Switch 662 may be a fluid switch as depicted in FIGS.24A-25B, or may be some other type of switch.

FIGS. 29A and 29B illustrate degradation of data by closing a switch. Inthis example, a portion 670 of a data storage device is shown, whichincludes substrate layer 672 and data storage medium 674, which containsdata 676. Leads 682 and 684 are connected to opposite sides of datastorage medium 674. Current source 678 and switch 680 are connected inseries. Current source 678 may be any structure capable of generating anelectric current or capable of having an electric current induced withinit. For example, the disk may include circuitry (e.g., a conductiveloop) for generating current on the disk by induction from magneticfields produced by nearby structures, such as the drive servo motor.When the switch is in a closed state 680′, as shown in FIG. 29B, currentpasses through data storage medium 674 to convert it to degraded state674′, so that data 676 is lost. In this example, data storage medium674′ has been converted to a state in which no data values are stored.

In other cases, data stored in a data storage medium may be modified, sothat the data stored therein is readable, but does not containmeaningful or useful information. For example in FIG. 30A, a portion 690of a data storage medium is shown which includes substrate 692 and datastorage medium 694 containing data 696. Voltage source 698 and switch700 are connected in series across data storage medium 694, by means ofleads 702 and 704. When switch 700 is opened, as indicated in FIG. 30Bby reference number 700′, data stored in data storage medium 694 isconverted to modified data 696′. For example, data 696, which included apattern of logical ‘1’s and ‘0’s, may be converted to a pattern of all‘1’s or all ‘0’s, as represented by the modified data 696′.

Fluid switches as depicted in FIGS. 26A, 26B, 27A and 27B utilize fluidto open or close an electrical circuit. By replacing electrical contactswith light conductors, an optical fluid switch could be constructed,which might be used to control the exposure of a light sensitive datastorage medium to light or control additional optical circuitry on thedisk.

As discussed above, in some embodiments, it may be desirable to produceor initiate data degradation of substrate, data, or data storage mediumonly after a selected number of uses or reads of the disk have beenperformed. Various methods may be devised to track the number of times adisk or other data storage device has been used based on the state ofthe disk. In some embodiments, the disk drive may be controlledappropriately to activate a different fluid release device upon each useof the device. In other embodiments, the disk may include multiplestructures that are activated in sequence over multiple uses of thedevice, where activation of each structure facilitates activation of thenext structure.

FIG. 31 illustrates a data storage device 800 with a fluid switch thatis activatable by multiple uses. In FIG. 31, fluid chamber 802 containsa conductive fluid 804 retained by barrier 806. First outward channelsegment 808 extends radially outward from fluid chamber 802 and leads tofirst distal channel segment 810. First distal channel segment 810connects to first inward channel segment 812, which lead to firstproximal channel segment 814. During a first use of data storage device800, data storage device 800 is rotated at a velocity that produces acentrifugal force in fluid 804 sufficient to break barrier 806,following which fluid 804 moves down first outward channel segment 808to first distal channel segment 810. Fluid 804 is retained in firstdistal channel segment 810 until rotation of data storage device 800decreases sufficiently, at the end of the first use. Fluid 804 thenmoves through first inward channel segment 812 to first proximal channelsegment 814, where it resides until the next use of the device. Notethat sizes and surface characteristics (hydrophilicity, hydrophobicity,etc.) of the various channel segments can be selected to promote desiredmovement of fluid in the channel segments, and that appropriateselection of channel dimensions and surface characteristics may generatecapillary forces that act in cooperation with forces generated byrotation of data storage device 800. During a second use of data storagedevice 800, fluid moves from first proximal channel segment 814, throughsecond outward channel segment 816 to second distal channel segment 818.At the end of the second use, fluid moves through second inward channelsegment 820 to second proximal channel segment 822, where it residesuntil the next use of the device. Finally, upon the third use of thedevice, fluid moves from second proximal channel segment 822, throughthird outward channel segment 824, and to third distal channel segment826. At the end of the third use, fluid moves through third inwardchannel segment 828 and into fluid chamber 830. Fluid chamber 830 mayinclude contacts 832 and 834, to form a fluid switch as describedpreviously in connection with FIGS. 26A-26B and 27A-27B. It should benoted that the dimensions of the fluid chambers and channels depicted inFIG. 31 are not exact, and that the actual dimensions of the fluidcontaining structures may be selected so that the entire fluid volumefrom fluid chamber 802 may be contained by each distal or proximalchannel segment, and, eventually, fluid chamber 830. When fluid fillsfluid chamber 830 to close the fluid switch and form a closed circuit byconnecting line 840 between electronic circuit components 836 and datastorage region 838), electronic components 836 cause a modification ofdata storage region 838. The modification may be any modification ofdata, data storage medium, or substrate, for example as described inconnection with any of FIGS. 28A-30B. In related embodiments, fluidchamber 830 may contain a degradation sensitive data storage medium thatis degradable upon exposure to a degradation inducing fluid.

As an alternative to using rotationally activated, fluid-mediatedmechanisms to produce modification to a data storage medium to renderdata unreadable or otherwise inaccessible, or to modify, destroy, orerase data, it may also be possible to use other types of rotationallyactivated mechanisms to produce modifications to a data storage device.FIGS. 32A and 32B depict a rotation activatable mechanical switch,including a cantilever made up of a beam 902 having at its end a mass904, within a chamber 906 formed in a substrate 908. Electrical contact910 is located in the wall of chamber 906 and connected to a lead 912.Electrical contact 914 is formed on mass 904 and connected to lead 916,which passes through beam 902. When mass 904 is subjected to sufficientforce, in the direction indicated by the arrow F in FIG. 32B, beam 902may flex, until contacts 910 and 914 touch to form an electricalconnection between leads 912 and 916.

Leads 912 and 916 may be connected to various electronic circuitcomponents, to produce modification of at least a portion of a datastorage device, e.g., as described in connection with FIGS. 28A-30B. Thesensitivity of the mechanical switch, i.e., the amount of force requiredto close the switch, may be controlled by selecting the mass of mass 904and stiffness of beam 902 appropriately.

FIG. 33 depicts different orientations of rotation activatablemechanical switches of the type depicted in FIGS. 32A and 32B,illustrating how different rotational forces may be used to activatesuch switches. In FIG. 33, a data storage device 950 includes a firstrotation activatable mechanical switch 952 and a second rotationactivatable mechanical switch 954. First rotation activatable mechanicalswitch 952 is oriented with mass 956 at the radial outward end of beam958, which runs in a radial direction. Beam 958 may be moved towardcontact 960 by inertial force F_(A) during angular acceleration in thedirection indicated by the arrow ω, which indicates angular velocity.F_(A) is proportional to the change in the angular velocity ω withrespect to time, dω/dt, and has a positive value when the data storagedevice is accelerating. F_(A) will be zero when the data storage deviceis rotating at a constant angular velocity, or when it is still. Duringangular deceleration, beam 958 may be moved toward contact 962, in theopposite direction of arrow ω, by inertial force F_(D). F_(D) isproportional to the change in the angular velocity ω with respect totime, dω/dt, and has a positive value when the data storage device isdecelerating. F_(D) will be zero when the data storage device isrotating at a constant angular velocity, or when it is still. Secondrotation activatable mechanical switch 954 is oriented with beam 964parallel to V_(T), the tangential velocity, and perpendicular to theradial direction. Switch 954 includes mass 966 at the end of beam 964.Second rotation activatable mechanical switch 954 may be activated whenby centrifugal force F_(C), which is proportional to the square of theangular velocity, ω². Accordingly, F_(C) will have a positive value forall non-zero values of angular velocity. By selecting the positioning ofa rotation activatable mechanical switch appropriately, the switch maybe made responsive to various combinations of forces associated withangular acceleration and centripetal acceleration (centrifugal forces).

Data storage devices according to embodiments as described above mayinclude a substrate configured for rotating access, a data storagemedium capable of storing machine-readable data carried by thesubstrate, and a rotation activatable switch configured to undergo achange in state in response to rotation to render unusable at least aportion of machine-readable data stored on the substrate. A change instate may include changing from an open configuration to a closedconfiguration, or changing from a closed to an open configuration. Insome embodiments, the rotation activatable switch may be a centrifugallyactivatable switch. In other embodiments, the rotation activatableswitch may be activatable by angular acceleration of said substrate, orby angular deceleration of said substrate. Various rotation activatableswitches designs may be used. The rotation activatable switch may be amicromechanical switch or a fluid switch. In some embodiments, therotation activatable switch may be a maintained contact switch, while inothers it may be a momentary contact switch. The rotation activatableswitch may include a cantilever. As depicted in FIGS. 32A and 32B, acantilever may include a beam having a mass at its end.

In some embodiments, e.g., as depicted in FIG. 44 the data storagedevice 1400 may include electronic circuitry 1402, and the rotationactivatable switch 1404 may be configured to control an electricalconnection between at least two portions of said electronic circuitry.Either opening or closing of a switch may be used to produce degradationor modification of data, data storage medium, or substrate in region1406. When rotation activatable switch 1404 is closed, contact 1408 incantilever 1410 touches contact 1412, connecting lines 1414 and 1416.The data storage device may include a power source 1418, and therotation activatable switch may be configured to control delivery ofpower from the power source to at least a portion of the data storagedevice. Line 1420 connects power source 1418 to region 1406 inelectronic circuit 1402. Various methods of producing degradation ormodification of data, data storage medium, or substrate with electroniccircuitry are shown in FIGS. 28A and B, FIGS. 29A and B and FIGS. 30 Aand B. The data storage device may include a power receiver coil, withthe rotation activatable switch configured to control the receipt ofpower by or distribution of power from the power receiver coil.

According to various embodiments, a limited use memory device mayinclude a substrate, machine-readable data stored on the substrate, andat least one centrifugally activatable switching mechanism on thesubstrate, with the switching mechanism configured to producemodification of a feature of the memory device. The feature may include,but is not limited to, an optical feature, an electrical feature, or amagnetic feature. The feature may be a feature of the substrate, themachine-readable data, the data storage medium in which themachine-readable data is stored, electronic circuitry on the substrate,or any of various other features that influence presence or readabilityof data. Modification of the feature may render at least a portion ofsaid machine-readable data inaccessible. In some embodiments,modification of the feature may disable reading of at least a portion ofthe machine-readable data from the data storage device. The portion ofmachine readable data comprises information necessary for readingadditional data from said data storage device. The information may be,for example, decryption key or index information. In some embodiments,modification of the feature may enable reading of at least a portion ofthe machine-readable data from the data storage device. Modification ofthe feature may cause destruction or modification of at least a portionof the machine-readable data, or it may include modification ofreadability of at least a portion of the machine-readable data. In someembodiments, prior to modification of the feature a first portion ofdata on the disk may be readable, and following modification of thefeature a second portion of data on the disk may be readable.

The limited use memory device may include a plurality of centrifugallyactivatable switching mechanisms that are activatable in sequence over aplurality of uses of the memory device and configured such thatactivation of the plurality of switching mechanisms renders at least aportion of the machine-readable data inaccessible. A use of the memorydevice may include subjecting the memory device to at least one ofangular acceleration or deceleration, for example. A disk 1500 with aplurality of rotation activatable mechanisms 1502, 1504, 1506, and 1508is depicted in FIG. 45. Operation of disk 1500 is substantially the sameas for the device depicted in FIG. 25, with mechanical switchingmechanisms in place of fluid switching mechanisms. As described inconnection with FIG. 25, rotation activatable mechanisms may beconfigured to be activated at different levels of centrifugal force,e.g., by adjusting the stiffness of the beam portion of each cantileverappropriately. Beam portion 1510 is indicated in rotation activatablemechanism 1502.

In some embodiments, the data storage device may be an opticallyreadable disk. In some embodiments, the centrifugally activatableswitching mechanism may be activatable by spinning the substrate in anoptical disk drive at normal read speeds, while in other embodiments,the centrifugally activatable switching mechanism may be activatable byspinning the substrate in an optical disk drive at speeds above normalread speeds. In some embodiments, the data storage device may be amagnetically readable disk, and the centrifugally activatable switchingmechanism may be activatable by spinning the substrate in a magneticdisk drive at normal read speeds, while in some embodiments, thecentrifugally activatable switching mechanism may be activatable byspinning the substrate in a magnetic disk drive at speeds above normalread speeds.

According to certain embodiments, the data storage device may include asubstrate, a data storage medium on the substrate that is degradableupon exposure to a degradation-inducing influence, and a rotationactivatable switching mechanism for controlling exposure of the datastorage medium to the degradation-inducing influence. Activation of therotation activatable switching mechanism may produce direct exposure ofthe data storage medium to the degradation-inducing influence, or it mayfacilitate degradation of the data storage medium by a secondarydegradation-inducing influence.

Secondary degradation inducing influences may include, for example,light, electromagnetic fields, and heat. The rotation activatableswitching mechanism may be a microswitch that is closable upon exposureto sufficient centrifugal force, such that closure of the microswitchpermits electrical current to flow into a selected portion of the datastorage device. A microswitch may include a microfabricated cantilever,for example, as depicted in FIGS. 32A and 32B.

As shown in FIGS. 46A and 46B, a data storage device 1550 may include asubstrate 1552, a degradation sensitive data storage medium 1554 onsubstrate 1552, with the data storage medium being degradable uponexposure to a degradation-inducing influence, and a rotation-responsivebarrier portion 1556 configured to shield data storage medium 1554 fromthe degradation-inducing influence. The degradation inducing influencemay be, for example, light. The rotation-responsive barrier portion 1556may include a removable barrier portion that, upon subjection tosufficient centrifugal force, is removable to permit exposure of thedata storage medium to the degradation-inducing influence. The barrierportion may be removed as at least one structural unit, as depicted inFIGS. 46A and 46B. Alternatively, the barrier portion may be removed byevaporation, as depicted in FIGS. 47A and 47B. Data storage device 1570includes substrate 1572, degradation sensitive data storage medium 1574,and evaporation sensitive barrier 1576. Following rotation of datastorage device 1570, evaporation sensitive barrier 1576 may becomessufficiently permeable or porous that a degradation inducing influencemay produce degradation of degradation sensitive data storage medium1574. Suitable materials for evaporation sensitive barrier 1576 mayinclude moisture permeable coatings, such as those having relativelyhigh water vapor transmission rates (WVTRs) that allow moisture or othermaterials to pass. In one approach, moisture passing through theevaporation sensitive barrier can degrade an underlying material. Inanother approach, moisture exiting through the evaporation sensitivebarrier 1576 permits drying of a material beneath the evaporationsensitive barrier 1576 and the dried material can block or diffuse lightor otherwise degrade data. In another embodiment, as depicted in FIGS.48A and 48B, a data storage device 1590 may include arotation-responsive barrier portion that may be a modifiable barrierportion 1592 that, upon being subjected to sufficient centrifugal forceis converted to a modified state 1592′ to permit exposure of the datastorage medium 1594 to the degradation-inducing influence. This mayoccur in a number of ways. For example, exposure of the barrier portion1592 to sufficient centrifugal force may modify an opticaltransmissivity, an electrical conductivity, or a permittivity of thebarrier portion. Suitable rotation sensitive materials for modifiablebarrier 1592 may include a liquid crystal or a MEMS structure, such asthe moving droplet structure described in Electrostatic Actuation ofMicroscale Liquid-Metal Droplets Laurent Latorre, Joonwon Kim, JunghoonLee, Associate Member, IEEE, Peter-Patrick de Guzman, Hyesog J. Lee,Pascal Nouet JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 11, NO. 4,AUGUST 2002, for example.

According to various embodiments as disclosed herein, use of a disk maybe controlled by a method that includes reading data from the disk androtating the disk to activate a rotation activatable mechanical switchon the disk. Rotating the disk to activate the rotation activatablemechanical switch may be performed prior to reading data from said disk,as illustrated in FIG. 36, subsequent to reading data from said disk, asillustrated in FIG. 35 or simultaneous with reading data from said disk,as illustrated in FIG. 37. The method may also include checking forprevious activation of the rotation activatable mechanical switch priorto reading data from said disk. In particular, reading data from thedisk may be performed if no previous activation of the rotationactivatable mechanical switch is detected, as exemplified by the methodof FIG. 39. Alternatively, reading data from the disk may be performedif no more than a selected number of previous activations of therotation activatable mechanical switch are detected, as shown in FIG.40. According to various methods disclosed herein, activation of therotation activatable mechanical switch causes degradation of a datastorage medium on the disk or modification of data stored on the disk.Activation of the rotation activatable mechanical switch may preventreading of at least a portion of data from the disk. In someembodiments, activation of the rotation activatable mechanical switchmay initiate a process wherein at least a portion of the data stored onthe disk is rendered unusable, modified, or destroyed.

A disk drive system suitable for use with various embodiments of datastorage devices as disclosed herein may include a receptacle forreceiving a substrate configured for rotating access having stored dataand a rotation activatable switching mechanism thereon, a read head forreading data from the substrate, a motor capable of spinning thesubstrate in a controlled pattern in response to a control signal, and adrive controller including one or more of control hardware, software, orfirmware configured to generate a control signal for causing the motorto spin said substrate in a controlled pattern sufficient to produceactivation of the rotation activatable switching mechanism. An exemplaryembodiment is depicted in FIG. 2. The drive may include a detectorcapable of sensing an outcome of activation of the rotation activatableswitching mechanism. In some embodiments of the disk drive system, theread head may be configured to function as the detector. The read headmay be, for example, and optical read head or a magnetic read head. Themotor may be capable of spinning the substrate at a speed higher thanthe normal read speed for the drive in order to produce activation ofthe rotation activatable switching mechanism.

Drive control software for controlling a disk drive for use with a diskhaving a rotation sensitive mechanism may include read head positioninstructions, including commands for controlling the position of a readhead with respect to a disk received in a disk drive, disk read positioninstructions including commands for controlling rotational movement of adisk received in the disk drive during reading, read instructions formanaging reading of data from the disk with a sensor; and datadegradation instructions for controlling duration and intensity ofrotation of the disk at levels sufficient to induce degradation in thedisk. In some embodiments, data degradation instructions may controldisk rotation to induce degradation of a data storage medium on thedisk. In some embodiments, data degradation instructions may controldisk rotation to induce degradation of a disk substrate.

A drive as described herein may be incorporated into a computer system,as shown in FIGS. 1 and 34, which may include various components such asa processor, a system bus, an input device, an output device, a drivecapable of reading data from a substrate configured for rotating access,and data storage media containing software instructions capable ofcontrolling said drive to produce rotation of the substrate of intensityand duration capable of activating a rotation activatable mechanism torender at least a portion of machine readable data stored on thesubstrate inaccessible.

Certain data storage devices as described herein may be manufacturedaccording to a method as shown in FIG. 49, which includes forming asubstrate configured for rotating access at step 1602, providing a datastorage medium on said substrate at step 1604, and forming an electricalcircuit on the substrate at step 1606. The electrical circuit mayinclude a rotation-activatable mechanical switch and be configured toproduce degradation of a least a portion of data stored in the datastorage medium upon activation of the rotation-activatable mechanicalswitch. The manufacturing method may also include a step of storingmachine readable data in the data storage medium. By combiningappropriately oriented rotation activatable fluid release and/orswitching mechanisms, which may include fluid and/or mechanicalswitches, with suitable fluid or electrical circuitry, it is possible toproduce a modification (e.g., activation or deactivation) of a datastorage device in following a selected number of uses of the device.Data storage devices configured in this manner may be used in varioussystems that utilize data storage devices. FIG. 34 illustrates a system1000 configured to make use of a data storage device 1010. The systemmay be a computer system, a CD or DVD player, or various other systemswhich may make use of data storage device configured for rotatingaccess. System 1000 includes CPU (central processing unit) 1002, systemmemory 1004, one or more I/O (input/output) devices 1006, and datastorage device drive 1008. Data storage device drive 1008 may be adaptedto receive a data storage device 1010. Data, power, and control signalsmay be transmitted between the various system components via bus 1012.System memory 1004 may include ROM 1014 and RAM 1016. Data storagedevice drive 1008 may be controlled by device driver software 1018resident in RAM 1016. Drive interface 1020, which may include hardware,software, or firmware, may assist the transfer of signals between datastorage device drive 1008 and the rest of system 1000. The operation ofdata storage device drive 1008 may be modified or controlled at thelevel of device driver software 1018, or drive interface 1020, as wellas by modifications to data storage device drive 1008. In someembodiments, data storage device 1010 may be configured so that it willbe modified or inactivated following a selected number of uses. In someembodiments, components of system 1000 other than data storage device1010 may operate in a conventional manner.

In other embodiments, selected components of system 1000 may includefeatures that are specialized for use with a data storage device 1010having rotation activatable features. System 1000 may be modified at thelevel of drive 1008, drive interface 1020, or program code 1018 residingin RAM 1016. Drive 1008 or drive interface 1020 may be modified at thehardware, firmware, or software level. Program code 1018 may be systemsoftware or application program software. As discussed previously inconnection with FIG. 25, system 1000 may be modified to control thespeed of rotation of data storage device 1010 within drive 1008 toactivate fluid release devices (or other rotation activatablemechanisms) in sequence based upon different thresholds for activation.System 1000 may be configured to detect prior activation of a rotationactivatable mechanism on data storage device 1010. Modifications to datastorage device 1010 associated with prior activation may be detected byvarious means. If the modification includes modification of data ormodification of accessibility of a particular portion of data, themodification may be detected when an attempt is made to read data fromdata storage device 1010, e.g. by failure of reading. In someembodiments, a rotation activatable mechanism may produce modificationof a mechanical, optical, electrical, magnetic, chemical, or otherproperty of the data storage device. Such modifications may bemanifested as modifications of data or accessibility of data, but arenot limited to modification of data or data accessibility. In someembodiments, modifications may be detectable by optical, electrical,magnetic, or other means, and the presence of the modification may serveas an instruction to the system to discontinue reading of the disk, orto operate in a specified manner (e.g., by increasing the speed ofrotation of the disk, delivering light to a selected region of the disk,etc.).

The following flow diagrams are illustrative of various approaches thatmay be taken for controlling operation of a system as depicted in FIG.33. Some approaches make use of conventional drive operation, whileothers may make use of modifications to conventional drive operation.

FIG. 35 is a flow diagram of a method of activating a rotationactivatable control mechanism. According to various embodiments,described previously, various rotation activatable mechanisms may beused to control access to data on a data storage device, by modifying ordegrading data, or by modifying access to the data by modifying all or aportion of the data storage device. Rotation activatable mechanisms maybe rotation activatable control mechanisms. At step 1052, data is readfrom a disk (or other data storage device configured for rotatingaccess). At step 1054, the disk is rotated to activate a rotationactivatable control mechanism. A rotation activatable control mechanismmay include, for example, a rotation activatable switch or fluid releasedevice, as described previously. Because the rotation activatablecontrol mechanism is activated after data is read from the device inthis example, the use of a rotation activated control mechanism thatproduces immediate (or substantially immediate) destruction of data, orotherwise rapidly renders data unusable or inaccessible may be used.Rotation activated control mechanisms that initiate a gradual process bywhich data is destroyed or rendered inaccessible may also be used.

FIG. 36 is a flow diagram of a further exemplary method of activating arotation activatable control mechanism. At step 1102, a disk is rotatedto activate a rotation activatable control mechanism. Subsequently, atstep 1104, data is read from the disk. In this example, the rotationactivatable control mechanism may initiate a process that causes data tobe destroyed or rendered unusable or inaccessible over time. Immediatedestruction of data may be incompatible with the subsequent step ofreading data from the disk.

FIG. 37 is a flow diagram of a further exemplary method includingactivation of a rotation activatable control mechanism. At step 1152, adata storage device configured for rotating access is rotated toactivate a rotation activatable control mechanism substantiallysimultaneously with reading of data from the data storage device.

FIG. 38 is a flow diagram providing further detail of method such asthat depicted in FIG. 34. At step 1202 of FIG. 38, data is read from adisk. Reading data from the disk may include rotating the disk to selecta location on the disk from which data is to be read. At step 1204, thedisk is rotated to open a rotation activatable barrier. Opening arotation activatable barrier may include rotating a disk atsubstantially the same velocity as used during reading data from thedisk, or it may include rotating the disk at a different velocity, in adifferent direction, or in some other pattern differing from therotation pattern used during reading of data from the disk. Fluid may bereleased by opening of the rotation activatable barrier, to producemodification of all or a portion of the data storage device by any ofvarious methods as described herein.

FIG. 39 is a flow diagram of a method in which a rotation activatablecontrol mechanism is used to control access to data on a disk. A processof reading data from a disk is initiated at step 1250. At decision point1252, a check is performed to determine whether a rotation activatablecontrol mechanism has been activated previously. Determination ofprevious activation of a rotation activatable control mechanism may beby various methods, as described previously, either through detectingthe inability to read data from the disk, the reading of ‘bad’ data fromthe disk, or the detecting of a modified feature of the disk. Ifprevious activation of a rotation activatable control mechanism is notdetected, process control moves to step 1254, and data is read from thedisk. After data is read from the disk, the disk is rotated to activatea rotation activatable control mechanism at step 1256. If subsequentattempts are made to read data from the disk, process control will beginagain at step 1250. When it is determined at step 1252 that the rotationactivatable control mechanism has been activated previously, the resultwill be affirmative, and the process will end (step 1258), and no datawill be read from the disk.

FIG. 40 is a flow diagram of a further embodiment of a method ofcontrolling access to data on a disk. In this exemplary embodiment,access to data on the disk is denied after a total of N accesses to thedata. After initiation of the method at step 1300, n, the number oftimes that a rotation activatable control mechanism on the disk has beenactivated, is determined at step 1302. If the disk has never beenactivated previously, zero activations will be detected. Activation of arotation activatable control mechanism may produce various types ofdetectable changes on a data storage device, including but not limitedto optically detectable changes, magnetically detectable changes,electrically detectable changes, among others. At decision point 1304,if n<N, process control moves to step 1306, where data is read from thedisk. At step 1308, the disk is rotated to activate a rotationactivatable control mechanism, increasing the number of detectablechanges on the disk by one. This is equivalent to increasing the valueof n to n+1.

Reading of data accomplished, the process ends at step 1310. If it isdesired to read data from the disk again, the process may be repeatedagain, starting at step 1300. When data has been read from the disk Ntimes, on the (N+1)th attempt to read data from the disk, at step 1302,a value of n=N will be obtained. At step 1304, the response to the queryn<N, will be ‘No’ and process control will jump to endpoint 1310. Thus,no further reads of data from the disk will be permitted. The methodpresented in FIG. 39 may be used, for example, in connection with a diskas shown in FIG. 25. Degradation of degradation sensitive regions 764,772, 780, 788 may be detected as an indicator of previous activation ofthe disk; when all four regions have been degraded, indicating that fourreads of the disk have been performed, then no further reading of datamay be permitted. Further reading may be prevented in by configuring thesoftware controlling reading of the disk so that it will not attempt aread when all degradation sensitive regions have been degraded (even ifthe data on the disk is present and readable). Alternatively, if thedegradation sensitive regions contain information necessary for readingdata from other portions of the disk (possibly redundant copies of thesame information, or possibly different information in differentdegradation sensitive regions) when all four degradation sensitiveregions have been degraded, the information necessary for reading datafrom the disk is no longer available on the disk.

FIG. 41 is a flow diagram of a method of manufacturing a data storagedevice according to various embodiments as disclosed herein. The methodincludes the steps of: forming a substrate configured for rotatingaccess at step 1322, providing a data storage medium on said substrateat step 1324, and forming a rotation-activatable fluid release mechanismon said substrate at step 1326. The rotation-activatable fluid releasemechanism may be configured to release fluid within said data storagedevice to produce degradation of at least a portion of data stored insaid data storage device. In related embodiments, the method may alsoinclude the steps of storing machine readable data in the data storagemedium, and loading the fluid release mechanism with a fluid.

FIG. 42 is a flow diagram of a method of operating a disk drive, whichincludes the steps of adjusting the radial position of a read head withrespect to a disk received in the disk drive, as shown at step 1332;controlling the rotation of a disk received in the disk drive to permitreading of data from the disk, as shown at step 1334; reading data fromthe disk with a sensor (step 1336); and, at step 1338, controllingrotation of the disk to produce activation of a rotation sensitivestructure configured to produce degradation of data on the disk.

In some embodiments, as described above, the disk drive may beconfigured for use with rotation-sensitive disks. FIG. 43 is a flowdiagram of a method of configuring a disk drive for use with arotation-sensitive disk. The method includes a first step 1352 ofproviding read head position instructions, including commands forcontrolling the position of a read head with respect to a disk receivedin the disk drive. Next, at step 1354, motor control instructionsincluding commands for controlling rotational movement of a diskreceived in the disk drive during reading are provided. At step 1356,read instructions for managing reading of data from the disk with asensor are provided. Finally, at step 1358, data degradationinstructions are provided for controlling duration and speed of rotationof the disk at levels sufficient to induce degradation in therotation-sensitive disk. One or more of the read head positioninstructions, motor control instructions, read instructions and datadegradation instructions may be provided in the form of software,hardware or firmware. For example, instructions may be provided on adisk that is provided to a purchaser of the disk drive, stored in staticor dynamic memory, or configured in an ASIC (application specificintegrated circuit) or other electronic circuitry. Memory or datastorage devices containing the instructions, or electronic circuitryembodying such instructions may be a part of the disk drive or part of acomputer or other device in which the disk drive may be installed.

With regard to the hardware and/or software used in the control ofdrives for data storage device according to the present embodiments, andparticularly to the control of data reading and disk rotation, thosehaving skill in the art will recognize that the state of the art hasprogressed to the point where there is little distinction left betweenhardware and software implementations of aspects of such systems; theuse of hardware or software is generally (but not always, in that incertain contexts the choice between hardware and software can becomesignificant) a design choice representing cost vs. efficiency orimplementation convenience tradeoffs. Those having skill in the art willappreciate that there are various vehicles by which processes and/orsystems described herein can be effected (e.g., hardware, software,and/or firmware), and that the preferred vehicle will vary with thecontext in which the processes are deployed. For example, if animplementer determines that speed and accuracy are paramount, theimplementer may opt for a hardware and/or firmware vehicle;alternatively, if flexibility is paramount, the implementer may opt fora solely software implementation; or, yet again alternatively, theimplementer may opt for some combination of hardware, software, and/orfirmware. Hence, there are several possible vehicles by which theprocesses described herein may be effected, none of which is inherentlysuperior to the other in that any vehicle to be utilized is a choicedependent upon the context in which the vehicle will be deployed and thespecific concerns (e.g., speed, flexibility, or predictability) of theimplementer, any of which may vary.

In some embodiments, portions of the subject matter described herein maybe implemented via Application Specific Integrated Circuits (ASICs),Field Programmable Gate Arrays (FPGAs), digital signal processors(DSPs), or other integrated formats. However, those skilled in the artwill recognize that some aspects of the embodiments disclosed herein, inwhole or in part, can be equivalently implemented in standard integratedcircuits, as one or more computer programs running on one or morecomputers (e.g., as one or more programs running on one or more computersystems), as one or more programs running on one or more processors(e.g., as one or more programs running on one or more microprocessors),as firmware, or as virtually any combination thereof, and that designingthe circuitry and/or writing the code for the software and/or firmwarewould be well within the capabilities of one of skill in the art inlight of this disclosure. In addition, those skilled in the art willappreciate that certain mechanisms of the subject matter describedherein are capable of being distributed as a program product in avariety of forms, and that an illustrative embodiment of the subjectmatter described herein applies equally regardless of the particulartype of signal bearing media used to actually carry out thedistribution. Examples of a signal bearing media include, but are notlimited to, the following: recordable type media such as floppy disks,hard disk drives, CD ROMs, digital tape, and computer memory; andtransmission type media such as digital and analog communication linksusing TDM or IP based communication links (e.g., links carryingpacketized data).

In a general sense, those skilled in the art will recognize that thevarious aspects described herein which can be implemented, individuallyand/or collectively, by a wide range of hardware, software, firmware, orany combination thereof can be viewed as being composed of various typesof “electrical circuitry.” Consequently, as used herein “electricalcircuitry” includes, but is not limited to, electrical circuitry havingat least one discrete electrical circuit, electrical circuitry having atleast one integrated circuit, electrical circuitry having at least oneapplication specific integrated circuit, electrical circuitry forming ageneral purpose computing device configured by a computer program (e.g.,a general purpose computer configured by a computer program which atleast partially carries out processes and/or devices described herein,or a microprocessor configured by a computer program which at leastpartially carries out processes and/or devices described herein),electrical circuitry forming a memory device (e.g., forms of randomaccess memory or an optical or ferromagnetic memory structure), and/orelectrical circuitry forming a communications device (e.g., a modem,communications switch, or optical-electrical equipment).

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beimplicitly understood by those with skill in the art that each functionand/or operation within such block diagrams, flowcharts, or examples canbe implemented, individually and/or collectively, by a wide range ofhardware, software, firmware, or virtually any combination thereof.

Those skilled in the art will recognize that it is common within the artto describe devices for data storage and reading in the fashion setforth herein, and thereafter use standard engineering practices tointegrate such described devices and/or processes into systems includingdata storage devices as exemplified herein. That is, at least a portionof the devices and/or processes described herein can be integrated intoa system including a data storage device via a reasonable amount ofexperimentation. Those having skill in the art will recognize that suchsystems generally include one or more of a memory such as volatile andnon-volatile memory, processors such as microprocessors and digitalsignal processors, computational-supporting or associated entities suchas operating systems, user interfaces, drivers, sensors, actuators,applications programs, one or more interaction devices, such as dataports, control systems including feedback loops and control implementingactuators (e.g., devices for sensing position and/or velocity and/oracceleration or time-rate-of-change thereof; control motors for movingand/or adjusting components and/or quantities). A typical system may beimplemented utilizing any suitable available components, such as thosetypically found in appropriate computing/communication systems and/ordata storage and reading systems, combined with standard engineeringpractices.

The foregoing-described aspects depict different components containedwithin, or connected with, different other components. It is to beunderstood that such depicted architectures are merely exemplary, andthat in fact many other architectures can be implemented which achievethe same functionality. In a conceptual sense, any arrangement ofcomponents to achieve the same functionality is effectively “associated”such that the desired functionality is achieved. Hence, any twocomponents herein combined to achieve a particular functionality can beseen as “associated with” each other such that the desired functionalityis achieved, irrespective of architectures or intermediate components.Likewise, any two components so associated can also be viewed as being“operably connected”, or “operably coupled”, to each other to achievethe desired functionality.

While particular aspects of the present subject matter described hereinhave been shown and described, it will be obvious to those skilled inthe art that, based upon the teachings herein, changes and modificationsmay be made without departing from this subject matter described hereinand its broader aspects and, therefore, the appended claims are toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of this subject matter describedherein. Furthermore, it is to be understood that the invention isdefined by the appended claims. It will be understood by those withinthe art that, in general, terms used herein, and especially in theappended claims (e.g., bodies of the appended claims) are generallyintended as “open” terms (e.g., the term “including” should beinterpreted as “including but not limited to,” the term “having” shouldbe interpreted as “having at least,” the term “includes” should beinterpreted as “includes but is not limited to,” etc.). It will befurther understood by those within the art that if a specific number ofan introduced claim recitation is intended, such an intent will beexplicitly recited in the claim, and in the absence of such recitationno such intent is present. For example, as an aid to understanding, thefollowing appended claims may contain usage of the introductory phrases“at least one” and “one or more” to introduce claim recitations.However, the use of such phrases should NOT be construed to imply thatthe introduction of a claim recitation by the indefinite articles “a” or“an” limits any particular claim containing such introduced claimrecitation to inventions containing only one such recitation, even whenthe same claim includes the introductory phrases “one or more” or “atleast one” and indefinite articles such as “a” or “an” (e.g., “a” and/or“an” should typically be interpreted to mean “at least one” and/or “oneor more”); the same holds true for the use of definite articles used tointroduce claim recitations. In addition, even if a specific number ofan introduced claim recitation is explicitly recited, those skilled inthe art will recognize that such recitation should typically beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, typicallymeans at least two recitations, or two or more recitations).Furthermore, in those instances where a convention analogous to “atleast one of A, B, and C, etc.” is used, in general such a constructionis intended in the sense of one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, and C”would include but not be limited to systems that have A alone, B alone,C alone, A and B together, A and C together, B and C together, and/or A,B, and C together). In those instances where a convention analogous to“at least one of A, B, or C, etc.” is used, in general such aconstruction is intended in the sense of one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, or C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together).

Although the methods, devices, systems and approaches herein have beendescribed with reference to certain preferred embodiments, otherembodiments are possible. As illustrated by the foregoing examples,various choices of system configuration may be within the scope of theinvention. As has been discussed, the choice of system configuration maydepend on the intended application of the system, the environment inwhich the system is used, cost, personal preference or other factors.Data storage device design, manufacture, and control processes may bemodified to take into account choices of system components andconfiguration, and such modifications, as known to those of skill in thearts of data storage and retrieval structures and systems, fluid controlstructures, and electronics design and construction, may fall within thescope of the invention. Therefore, the full spirit or scope of theinvention is defined by the appended claims and is not to be limited tothe specific embodiments described herein.

1. A method of manufacturing a data storage device, comprising: forminga substrate configured for rotating access; providing a data storagemedium on said substrate; and forming an electrical circuit on saidsubstrate, said electrical circuit including a rotation-activatablemechanical switch and configured to produce degradation of at least aportion of data stored in said data storage medium upon activation ofsaid rotation-activatable mechanical switch.
 2. The method of claim 1,further comprising: storing machine readable data in said data storagemedium.
 3. The method of claim 1, wherein forming an electrical circuiton the substrate includes forming an electrical circuit including arotation-activatable mechanical switch oriented to close in response toangular acceleration.
 4. The method of claim 1, wherein forming anelectrical circuit on the substrate includes forming an electricalcircuit including a rotation-activatable mechanical switch oriented toclose in response to angular deceleration.
 5. The method of claim 1,wherein forming an electrical circuit on the substrate includes formingan electrical circuit including a rotation-activatable mechanical switchoriented to close in response to centripetal acceleration.
 6. The methodof claim 1, wherein forming an electrical circuit on the substrateincludes forming an electrical circuit including a rotation-activatablemechanical switch oriented to close in response to centripetaldeceleration.
 7. The method of claim 1, wherein forming an electricalcircuit on the substrate includes forming an electrical circuitincluding a rotation-activatable mechanical momentary-contact switch. 8.The method of claim 1, wherein forming an electrical circuit on thesubstrate includes forming an electrical circuit including arotation-activatable mechanical maintained contact switch.
 9. The methodof claim 1, wherein providing a data storage medium on said substrateincludes providing a degradable data storage medium, and wherein saidelectrical circuit is configured to produce degradation of said at leasta portion of data stored in said data storage medium through degradationof said data storage medium.
 10. The method of claim 1, whereinproviding a data storage medium on said substrate includes providing adegradable data storage medium, and wherein said electrical circuit isconfigured to produce degradation of said at least a portion of datastored in said data storage medium through modification of data storedin said data storage medium.
 11. The method of claim 1, wherein saidelectrical circuit is configured to produce degradation of said at leasta portion of data stored in said data storage medium through degradationof data stored in said data storage medium.
 12. The method of claim 1,wherein said electrical circuit is configured to produce degradation ofsaid at least a portion of data stored in said data storage mediumthrough degradation of data stored in said data storage medium.
 13. Themethod of claim 1, wherein said electrical circuit is configured toproduce degradation of said at least a portion of data stored in saiddata storage medium through degradation of said substrate.